Crude: "This use of multiple inheritance is crude...."

The simplest and most obvious use of multiple inheritance is to ‘‘glue’’ two otherwise unrelated classes together as part of the implementation of a third class. The S a t e l l i t e class built out of the
T a s k and D i s p l a y e d classes in §15.2 is an example of this. This use of multiple inheritance is crude, effective, and important, but not very interesting. Basically, it saves the programmer from
writing a lot of forwarding functions. from << The C++ programming language>> page 399What's the meaning of curde in above sentence ? Does it mean "Natural" or "awkward" ?
My interpretation would be "Natural", because the dictionary says so. but the book in our language describe it as "awkward,abrupt ".

"This use of multiple inheritance is crude, effective, and important, but not very interesting"
But "effective", "important" are good thing. If the author means "curde" in bad way, it should go with "not very intereting".
That would be easy to see his point. So I am confused.
And dictionary says if a substance is crude, it is untouched(natural). If a production is crude, then it is not a good one.

I probably should have mentioned earlier that 'crude' is often situated quite close to 'effective'. I'm not sure if I'd describe it as a collocation, or a set phrase, but it's quite close to being one or the other. 'Crude but effective' in context would, I imagine, generate a fair few hits ... let's see: "Crude but effective" ... only four!? Maybe not quite the cliché I'd imagined it to be.

I have my doubts about 'blunt but effective' (phew - no results). And 'crude facts' sounds rather dismissive, to my ear. (Welcome to the Forum, Couriosity )